The flaps of corrugated cardboard packaging boxes are sealed usually by affixing a sealing tape to the joint of the flaps or by driving staples into the flap joint with a boxer. When the flaps sealed by such a method are opened, the flaps become damaged on the surface and require the use of a new sealing tape or staples for resealing. Although a method of fastening by reeving a string around tacks with disks is adapted for easy resealing, it takes some time to fix the disk holding tacks in place, and the method has another drawback that the fastening means is easily removable during the transport or handling of the package, failing to seal the package reliably.
In view of these problems, a fastener has been developed which facilitates sealing and opening of packages and which is reusable. FIG. 1 shows the construction of the fastener. The fastener comprises a flat main plate 1 as its main body and a pair of turnable pieces 2a, 2b hingedly connected at a thin wall portion to the flat main plate. The pair of turnable pieces 2a, 2b can be raised from the surface of the main plate 1 and turned to the position flush with the surface. When the pieces 2a, 2b are so turned, the forward ends of the pieces 2a, 2b slightly project beyond the ends of the main plate 1. The projecting portions serve as knobs. The main plate 1 has recesses 3a, 3b into which the pair of turnable pieces 2a, 2b are fittable respectively when turned downward. Apertures 4a, 4b are formed in the main portions of the recesses 3a, 3b. The turnable pieces 2a, 2b are provided with sharpened piercing nails 5a, 5b on their lower sides. The piercing nails 5a, 5b are opposed to the apertures 4a, 4b and are each in the form of a cow horn curved toward the center. Engaging pieces 6a, 6b on the rear sides of the turnable pieces 2a, 2b are engageable with engagement projections 7a, 7b on the inner side edges of the recessed portions 3a, 3b of the main plate 1. These portions are made integrally from a flexible synthetic resin, such as polypropylene. A large number of such fasteners are connected together by connectors 8.
As seen in FIG. 2, the faster is placed across the opposed edges of flaps 9a, 9b of a corrugated cardboard packaging box. When the turnable pieces 2a, 2b are turned and pressed downward as shown in FIG. 3, the piercing nails 5a, 5b are driven through the flaps 9a, 9b and an underlying flap 9c to fasten the flaps 9a, 9b and 9c together as held between the lower side of the main plate 1 and the nails, whereby the flaps 9a, 9b are sealed. To open the flaps 9a, 9b, the fastener is removable by raising the turnable pieces 2a, 2b at the knob end portions and thereby withdrawing the piercing nails 5a, 5b from the flaps 9a, 9b, 9c. The fastener is reusable in the same manner as above for resealing.
Such fasteners are inefficient to use for sealing if handled individually, so that it is desired to connect together a large number of fasteners and attach them in place one after another by some device.